Maou Shaitan Geneha, a demon lord whose powers were sealed away, seeks out the descendant of the one who sealed her; company employee Shishibe Yashiro. Wanting Yashiro to undo the seal, Maou forms a contract with her, aiming to satisfy Yashiro in the hopes that she'll undo the seal.
Demon Lord of "Yashiro" is a completed manga by Kuroda bb, first published in 2024. It blends comedy, girls' love, fantasy and slice of life. You can read all 14 available chapters of Demon Lord of "Yashiro" online for free on MangaPulse; the newest is Chapter 13, added 2025-04-30. The series is finished, so you can read it from start to end in one go.